Abstract: A user of a software application presented herein can notify other registered users of the software application of undesirable conditions of a vehicle associated with a user account. A first user observes a vehicle in an undesirable state (as specified in each of the respective figures). Using the software application, the first user enters a license plate number (or other identification) of the vehicle. The software application determines that the vehicle's license plate number is associated with a user account of a second user. The first user can then navigate a graphical user interface to send a message to the second user related to the vehicle condition. A service provider system can be configured to manage user accounts, direct messages between users, and/or provide other services related to the software application.